They gave him easy stuff to do, such as miming a scene while someone else did the voice.

So Jon and I were standing there, miming this scene from Moonlight Mile - and have I mentioned just how scrumptious Jake Gyllenhaal looks in this movie, with the doe eyes and the buttery, knobby shoulders?

Origen

This word comes from Greek pantomimos ‘imitator of all’. In Latin pantomimus was used for an actor using mime. This later developed into a comic dramatization with the stock characters of Clown, Pantaloon ( see pantaloons), Harlequin, and Columbine. The familiar panto based on fairy tales such as Mother Goose or Cinderella and involving music, topical jokes, and slapstick comedy developed in the 19th century, with a new set of conventional characters including the dame, the principal boy, and the pantomime horse. Mime (early 17th century) and mimic (late 16th century) come from the same root.